Two human rotavirus cell-culture isolates (strains D [VP4:1A; VP7:1], and DS-1 [VP4:1B; VP7:2]) as well as two human x human rotavirus reassortants (Wa x P [VP4:1A; VP7:3] and Wa x DA-1 [VP4:1A; VP7:2]) have been successfully adapted to grow in primary African Green Monkey kidney cells at the suboptimal temperature of 30oC, 28oC, or 26oC. These rotavirus strains were cold-adapted to determine whether cold-adapted (ca) mutants selected by this strategy are attenuated and suitable for use in a live virus vaccine. The 26oC and 28oC ca mutants of the D, DS-1, Wa x P, and Wa x DS-1 viruses have been plaque-purified and their phenotypes have been characterized.